Secondary Cell Link Recovery Request Transmission

ABSTRACT

Embodiments are presented herein of apparatuses, systems, and methods for a user equipment device (UE) to transmit an indication of a link failure on a secondary cell. The indication may be transmitted on resources selected based on one or more conditions. One or more priority rules may be used to resolve collisions. The UE may further make an assumption of a beam or beams to use for communications with the secondary cell following the link failure and prior to receiving an indication from the network of a selected beam.

PRIORITY DATA

This application claims benefit of priority to Chinese Application No.201910920468.5, titled “Secondary Cell Link Recovery RequestTransmission”, filed Sep. 27, 2019, which is hereby incorporated byreference in its entirety as though fully and completely set forthherein.

TECHNICAL FIELD

The present application relates to wireless devices, and moreparticularly to apparatuses, systems, and methods for secondary celllink recovery.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Wirelessdevices, particularly wireless user equipment devices (UEs), have becomewidespread. Additionally, there are a variety of applications (or apps)hosted on UEs that perform or depend on wireless communication, such asapplications that provide messaging, email, browsing, video streaming,short video, voice streaming, real-time gaming, or various other onlineservices.

In some instances, a link between a secondary cell (SCell) and a UE maybe lost. Recovering the SCell link may take time and/or conflict withother priorities. Thus, improvements in the field are desirable.

SUMMARY

Techniques, apparatuses, systems, and methods are disclosed for a userequipment device (UE) to recover a link with a secondary cell (SCell).In some embodiments, after detecting the SCell link failure, the UE maydetermine one or more conditions. Based on the one or more conditions,the UE may select time and frequency resources to transmit an indicationof the SCell link failure to a network. Additionally, the UE may selectan uplink and/or downlink beam to use prior to receiving a beamindication from the network.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the disclosed embodiments can be obtained whenthe following detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 illustrates an example wireless communication system, accordingto some embodiments;

FIG. 2 illustrates a base station (BS) in communication with a userequipment (UE) device, according to some embodiments;

FIG. 3 illustrates an example block diagram of a UE, according to someembodiments;

FIG. 4 illustrates an example block diagram of a BS, according to someembodiments;

FIG. 5 illustrates an example block diagram of cellular communicationcircuitry, according to some embodiments;

FIGS. 6 and 7 illustrate examples of a 5G NR base station (gNB),according to some embodiments;

FIG. 8 is a communication diagram illustrating SCell link recoverymessages, according to some embodiments;

FIG. 9 is a flow chart diagram illustrating an example method forsecondary cell (SCell) link recovery, according to some embodiments;

FIGS. 10 and 11 are timelines of SCell link recovery messageopportunities, according to some embodiments;

FIG. 12 is a communication diagram illustrating SCell link recoverymessages using random access, according to some embodiments;

FIG. 13 illustrates potential collisions with SCell link recoverymessages, according to some embodiments; and

FIG. 14 is a timeline of SCell link recovery messages and beamselection, according to some embodiments.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and are herein described in detail. It should beunderstood, however, that the drawings and detailed description theretoare not intended to limit the invention to the particular formdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS Acronyms

The following acronyms may be used in the present Patent Application:

-   UE: User Equipment-   BS: Base Station-   ENB: eNodeB (Base Station)-   LTE: Long Term Evolution-   UMTS: Universal Mobile Telecommunications System-   RAT: Radio Access Technology-   RAN: Radio Access Network-   E-UTRAN: Evolved UMTS Terrestrial RAN-   CN: Core Network-   EPC: Evolved Packet Core-   MME: Mobile Management Entity-   HSS: Home Subscriber Server-   SGW: Serving Gateway-   PS: Packet-Switched-   CS: Circuit-Switched-   EPS: Evolved Packet-Switched System-   RRC: Radio Resource Control-   IE: Information Element

Terms

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Wireless Device—any of various types of computer system devices whichperforms wireless communications. A wireless device can be portable (ormobile) or may be stationary or fixed at a certain location. A UE is anexample of a wireless device.

Communication Device—any of various types of computer systems or devicesthat perform communications, where the communications can be wired orwireless. A communication device can be portable (or mobile) or may bestationary or fixed at a certain location. A wireless device is anexample of a communication device. A UE is another example of acommunication device.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless telephone system or radio system.

Processing Element—refers to various elements or combinations ofelements that are capable of performing a function in a device, such asa user equipment or a cellular network device. Processing elements mayinclude, for example: processors and associated memory, portions orcircuits of individual processor cores, entire processor cores,processor arrays, circuits such as an ASIC (Application SpecificIntegrated Circuit), programmable hardware elements such as a fieldprogrammable gate array (FPGA), as well any of various combinations ofthe above.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since characteristics of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein may be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 Mhz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Band—The term “band” has the full breadth of its ordinary meaning, andat least includes a section of spectrum (e.g., radio frequency spectrum)in which channels are used or set aside for the same purpose.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thus,the term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

Approximately—refers to a value that is almost correct or exact. Forexample, approximately may refer to a value that is within 1 to 10percent of the exact (or desired) value. It should be noted, however,that the actual threshold value (or tolerance) may be applicationdependent. For example, in some embodiments, “approximately” may meanwithin 0.1% of some specified or desired value, while in various otherembodiments, the threshold may be, for example, 2%, 3%, 5%, and soforth, as desired or as required by the particular application.

Concurrent—refers to parallel execution or performance, where tasks,processes, or programs are performed in an at least partiallyoverlapping manner. For example, concurrency may be implemented using“strong” or strict parallelism, where tasks are performed (at leastpartially) in parallel on respective computational elements, or using“weak parallelism”, where the tasks are performed in an interleavedmanner, e.g., by time multiplexing of execution threads.

Configured to—Various components may be described as “configured to”perform a task or tasks. In such contexts, “configured to” is a broadrecitation generally meaning “having structure that” performs the taskor tasks during operation. As such, the component can be configured toperform the task even when the component is not currently performingthat task (e.g., a set of electrical conductors may be configured toelectrically connect a module to another module, even when the twomodules are not connected). In some contexts, “configured to” may be abroad recitation of structure generally meaning “having circuitry that”performs the task or tasks during operation. As such, the component canbe configured to perform the task even when the component is notcurrently on. In general, the circuitry that forms the structurecorresponding to “configured to” may include hardware circuits.

Various components may be described as performing a task or tasks, forconvenience in the description. Such descriptions should be interpretedas including the phrase “configured to.” Reciting a component that isconfigured to perform one or more tasks is expressly intended not toinvoke 35 U.S.C. § 112(f) interpretation for that component.

FIGS. 1 and 2—Communication System

FIG. 1 illustrates a simplified example wireless communication system,according to some embodiments. It is noted that the system of FIG. 1 ismerely one example of a possible system, and that features of thisdisclosure may be implemented in any of various systems, as desired.

As shown, the example wireless communication system includes a basestation 102 which communicates over a transmission medium with one ormore user devices 106A, 106B, etc., through 106N. Each of the userdevices may be referred to herein as a “user equipment” (UE). Thus, theuser devices 106 are referred to as UEs or UE devices.

The base station (BS) 102 may be a base transceiver station (BTS) orcell site (a “cellular base station”), and may include hardware thatenables wireless communication with the UEs 106A through 106N.

The communication area (or coverage area) of the base station may bereferred to as a “cell.” The base station 102 and the UEs 106 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs), also referred to as wirelesscommunication technologies, or telecommunication standards, such as GSM,UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces),LTE, LTE-Advanced (LTE-A), 5G new radio (5G NR), HSPA, 3GPP2 CDMA2000(e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc. Note that if the base station102 is implemented in the context of LTE, it may alternately be referredto as an ‘eNodeB’ or ‘eNB’. Note that if the base station 102 isimplemented in the context of 5G NR, it may alternately be referred toas gNodeB' or ‘gNB’.

As shown, the base station 102 may also be equipped to communicate witha network 100 (e.g., a core network of a cellular service provider, atelecommunication network such as a public switched telephone network(PSTN), and/or the Internet, among various possibilities). Thus, thebase station 102 may facilitate communication between the user devicesand/or between the user devices and the network 100. In particular, thecellular base station 102 may provide UEs 106 with varioustelecommunication capabilities, such as voice, SMS and/or data services.

Base station 102 and other similar base stations operating according tothe same or a different cellular communication standard may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UEs 106A-N and similar devices over ageographic area via one or more cellular communication standards.

Thus, while base station 102 may act as a “serving cell” for UEs 106A-Nas illustrated in FIG. 1, each UE 106 may also be capable of receivingsignals from (and possibly within communication range of) one or moreother cells (which might be provided by other base stations 102B-N),which may be referred to as “neighboring cells”. Such cells may also becapable of facilitating communication between user devices and/orbetween user devices and the network 100. Such cells may include “macro”cells, “micro” cells, “pico” cells, and/or cells which provide any ofvarious other granularities of service area size. Other configurationsare also possible.

In some embodiments, base station 102 may be a next generation basestation, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In someembodiments, a gNB may be connected to a legacy evolved packet core(EPC) network and/or to a NR core (NRC) network. In addition, a gNB cellmay include one or more transition and reception points (TRPs). Inaddition, a UE capable of operating according to 5G NR may be connectedto one or more TRPs within one or more gNBs.

Note that a UE 106 may be capable of communicating using multiplewireless communication standards. For example, the UE 106 may beconfigured to communicate using a wireless networking (e.g., Wi-Fi)and/or peer-to-peer wireless communication protocol (e.g., Bluetooth,Wi-Fi peer-to-peer, etc.) in addition to at least one cellularcommunication protocol (e.g., GSM, UMTS (associated with, for example,WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc.). The UE 106 may alsoor alternatively be configured to communicate using one or more globalnavigational satellite systems (GNSS, e.g., GPS or GLONASS), one or moremobile television broadcasting standards (e.g., ATSC-M/H), and/or anyother wireless communication protocol, if desired. Other combinations ofwireless communication standards (including more than two wirelesscommunication standards) are also possible.

FIG. 2 illustrates user equipment 106 (e.g., one of the devices 106Athrough 106N) in communication with a base station 102, according tosome embodiments. The UE 106 may be a device with cellular communicationcapability such as a mobile phone, a hand-held device, a computer or atablet, or virtually any type of wireless device.

The UE 106 may include a processor that is configured to execute programinstructions stored in memory. The UE 106 may perform any of the methodembodiments described herein by executing such stored instructions.Alternatively, or in addition, the UE 106 may include a programmablehardware element such as an FPGA (field-programmable gate array) that isconfigured to perform any of the method embodiments described herein, orany portion of any of the method embodiments described herein.

The UE 106 may include one or more antennas for communicating using oneor more wireless communication protocols or technologies. In someembodiments, the UE 106 may be configured to communicate using, forexample, CDMA2000 (1xRTT / 1xEV-DO/HRPD/eHRPD) or LTE using a singleshared radio and/or GSM or LTE using the single shared radio. The sharedradio may couple to a single antenna, or may couple to multiple antennas(e.g., for multiple-input, multiple-output or “MIMO”) for performingwireless communications. In general, a radio may include any combinationof a baseband processor, analog RF signal processing circuitry (e.g.,including filters, mixers, oscillators, amplifiers, etc.), or digitalprocessing circuitry (e.g., for digital modulation as well as otherdigital processing). Similarly, the radio may implement one or morereceive and transmit chains using the aforementioned hardware. Forexample, the UE 106 may share one or more parts of a receive and/ortransmit chain between multiple wireless communication technologies,such as those discussed above.

In some embodiments, the UE 106 may include any number of antennas andmay be configured to use the antennas to transmit and/or receivedirectional wireless signals (e.g., beams). Similarly, the BS 102 mayalso include any number of antennas and may be configured to use theantennas to transmit and/or receive directional wireless signals (e.g.,beams). To receive and/or transmit such directional signals, theantennas of the UE 106 and/or BS 102 may be configured to applydifferent “weight” to different antennas. The process of applying thesedifferent weights may be referred to as “precoding”.

In some embodiments, the UE 106 may include separate transmit and/orreceive chains (e.g., including separate antennas and other radiocomponents) for each wireless communication protocol with which it isconfigured to communicate. As a further possibility, the UE 106 mayinclude one or more radios which are shared between multiple wirelesscommunication protocols, and one or more radios which are usedexclusively by a single wireless communication protocol. For example,the UE 106 might include a shared radio for communicating using eitherof LTE or 5G NR (or LTE or 1xRTTor LTE or GSM), and separate radios forcommunicating using each of Wi-Fi and Bluetooth. Other configurationsare also possible.

FIG. 3—Block Diagram of a UE

FIG. 3 illustrates an example simplified block diagram of acommunication device 106, according to some embodiments. It is notedthat the block diagram of the communication device of FIG. 3 is only oneexample of a possible communication device. According to embodiments,communication device 106 may be a user equipment (UE) device, a mobiledevice or mobile station, a wireless device or wireless station, adesktop computer or computing device, a mobile computing device (e.g., alaptop, notebook, or portable computing device), a tablet and/or acombination of devices, among other devices. As shown, the communicationdevice 106 may include a set of components 300 configured to performcore functions. For example, this set of components may be implementedas a system on chip (SOC), which may include portions for variouspurposes. Alternatively, this set of components 300 may be implementedas separate components or groups of components for the various purposes.The set of components 300 may be coupled (e.g., communicatively;directly or indirectly) to various other circuits of the communicationdevice 106.

For example, the communication device 106 may include various types ofmemory (e.g., including NAND flash 310), an input/output interface suchas connector I/F 320 (e.g., for connecting to a computer system; dock;charging station; input devices, such as a microphone, camera, keyboard;output devices, such as speakers; etc.), the display 360, which may beintegrated with or external to the communication device 106, andcellular communication circuitry 330 such as for 5G NR, LTE, GSM, etc.,and short to medium range wireless communication circuitry 329 (e.g.,Bluetooth™ and WLAN circuitry). In some embodiments, communicationdevice 106 may include wired communication circuitry (not shown), suchas a network interface card, e.g., for Ethernet.

The cellular communication circuitry 330 may couple (e.g.,communicatively; directly or indirectly) to one or more antennas, suchas antennas 335 and 336 as shown. The short to medium range wirelesscommunication circuitry 329 may also couple (e.g., communicatively;directly or indirectly) to one or more antennas, such as antennas 337and 338 as shown. Alternatively, the short to medium range wirelesscommunication circuitry 329 may couple (e.g., communicatively; directlyor indirectly) to the antennas 335 and 336 in addition to, or insteadof, coupling (e.g., communicatively; directly or indirectly) to theantennas 337 and 338. The short to medium range wireless communicationcircuitry 329 and/or cellular communication circuitry 330 may includemultiple receive chains and/or multiple transmit chains for receivingand/or transmitting multiple spatial streams, such as in amultiple-input multiple output (MIMO) configuration.

In some embodiments, as further described below, cellular communicationcircuitry 330 may include dedicated receive chains (including and/orcoupled to, e.g., communicatively, directly or indirectly, dedicatedprocessors and/or radios) for multiple RATs (e.g., a first receive chainfor LTE and a second receive chain for 5G NR). In addition, in someembodiments, cellular communication circuitry 330 may include a singletransmit chain that may be switched between radios dedicated to specificRATs. For example, a first radio may be dedicated to a first RAT, e.g.,LTE, and may be in communication with a dedicated receive chain and atransmit chain shared with an additional radio, e.g., a second radiothat may be dedicated to a second RAT, e.g., 5G NR, and may be incommunication with a dedicated receive chain and the shared transmitchain.

The communication device 106 may also include and/or be configured foruse with one or more user interface elements. The user interfaceelements may include any of various elements, such as display 360 (whichmay be a touchscreen display), a keyboard (which may be a discretekeyboard or may be implemented as part of a touchscreen display), amouse, a microphone and/or speakers, one or more cameras, one or morebuttons, and/or any of various other elements capable of providinginformation to a user and/or receiving or interpreting user input.

The communication device 106 may further include one or more smart cards345 that include SIM (Subscriber Identity Module) functionality, such asone or more UICC(s) (Universal Integrated Circuit Card(s)) cards 345.

As shown, the SOC 300 may include processor(s) 302, which may executeprogram instructions for the communication device 106 and displaycircuitry 304, which may perform graphics processing and provide displaysignals to the display 360. The processor(s) 302 may also be coupled tomemory management unit (MMU) 340, which may be configured to receiveaddresses from the processor(s) 302 and translate those addresses tolocations in memory (e.g., memory 306, read only memory (ROM) 350, NANDflash memory 310) and/or to other circuits or devices, such as thedisplay circuitry 304, short range wireless communication circuitry 229,cellular communication circuitry 330, connector I/F 320, and/or display360. The MMU 340 may be configured to perform memory protection and pagetable translation or set up. In some embodiments, the MMU 340 may beincluded as a portion of the processor(s) 302.

As noted above, the communication device 106 may be configured tocommunicate using wireless and/or wired communication circuitry. Thecommunication device 106 may be configured to transmit a request toattach to a first network node operating according to the first RAT andtransmit an indication that the wireless device is capable ofmaintaining substantially concurrent connections with the first networknode and a second network node that operates according to the secondRAT. The wireless device may also be configured transmit a request toattach to the second network node. The request may include an indicationthat the wireless device is capable of maintaining substantiallyconcurrent connections with the first and second network nodes. Further,the wireless device may be configured to receive an indication that dualconnectivity (DC) with the first and second network nodes has beenestablished.

As described herein, the communication device 106 may include hardwareand software components for implementing features for using multiplexingto perform transmissions according to multiple radio access technologiesin the same frequency carrier (e.g., and/or multiple frequencycarriers), as well as the various other techniques described herein. Theprocessor 302 of the communication device 106 may be configured toimplement part or all of the features described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively (or inaddition), processor 302 may be configured as a programmable hardwareelement, such as an FPGA (Field Programmable Gate Array), or as an ASIC(Application Specific Integrated Circuit). Alternatively (or inaddition) the processor 302 of the communication device 106, inconjunction with one or more of the other components 300, 304, 306, 310,320, 329, 330, 340, 345, 350, 360 may be configured to implement part orall of the features described herein.

In addition, as described herein, processor 302 may include one or moreprocessing elements. Thus, processor 302 may include one or moreintegrated circuits (ICs) that are configured to perform the functionsof processor 302. In addition, each integrated circuit may includecircuitry (e.g., first circuitry, second circuitry, etc.) configured toperform the functions of processor(s) 302.

Further, as described herein, cellular communication circuitry 330 andshort range wireless communication circuitry 329 may each include one ormore processing elements and/or processors. In other words, one or moreprocessing elements or processors may be included in cellularcommunication circuitry 330 and, similarly, one or more processingelements or processors may be included in short range wirelesscommunication circuitry 329. Thus, cellular communication circuitry 330may include one or more integrated circuits (ICs) that are configured toperform the functions of cellular communication circuitry 330. Inaddition, each integrated circuit may include circuitry (e.g., firstcircuitry, second circuitry, etc.) configured to perform the functionsof cellular communication circuitry 330. Similarly, the short rangewireless communication circuitry 329 may include one or more ICs thatare configured to perform the functions of short range wirelesscommunication circuitry 329. In addition, each integrated circuit mayinclude circuitry (e.g., first circuitry, second circuitry, etc.)configured to perform the functions of short range wirelesscommunication circuitry 329.

FIG. 4—Block Diagram of a Base Station

FIG. 4 illustrates an example block diagram of a base station 102,according to some embodiments. It is noted that the base station of FIG.4 is merely one example of a possible base station. As shown, the basestation 102 may include processor(s) 404 which may execute programinstructions for the base station 102. The processor(s) 404 may also becoupled to memory management unit (MMU) 440, which may be configured toreceive addresses from the processor(s) 404 and translate thoseaddresses to locations in memory (e.g., memory 460 and read only memory(ROM) 450) or to other circuits or devices.

The base station 102 may include at least one network port 470. Thenetwork port 470 may be configured to couple to a telephone network andprovide a plurality of devices, such as UE devices 106, access to thetelephone network as described above in FIGS. 1 and 2.

The network port 470 (or an additional network port) may also oralternatively be configured to couple to a cellular network, e.g., acore network of a cellular service provider. The core network mayprovide mobility related services and/or other services to a pluralityof devices, such as UE devices 106. In some cases, the network port 470may couple to a telephone network via the core network, and/or the corenetwork may provide a telephone network (e.g., among other UE devicesserviced by the cellular service provider).

In some embodiments, base station 102 may be a next generation basestation, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In suchembodiments, base station 102 may be connected to a legacy evolvedpacket core (EPC) network and/or to a NR core (NRC) network. Inaddition, base station 102 may be considered a 5G NR cell and mayinclude one or more transition and reception points (TRPs). In addition,a UE capable of operating according to 5G NR may be connected to one ormore TRPs within one or more gNB s.

The base station 102 may include at least one antenna 434, and possiblymultiple antennas. The radio 430 and at least one antenna 434 may beconfigured to operate as a wireless transceiver and may be furtherconfigured to communicate with UE devices 106. The antenna 434 maycommunicate with the radio 430 via communication chain 432.Communication chain 432 may be a receive chain, a transmit chain orboth. The radio 430 may be configured to communicate via variouswireless communication standards, including, but not limited to, 5G NR,LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

The base station 102 may be configured to communicate wirelessly usingmultiple wireless communication standards. In some instances, the basestation 102 may include multiple radios, which may enable the basestation 102 to communicate according to multiple wireless communicationtechnologies. For example, as one possibility, the base station 102 mayinclude an LTE radio for performing communication according to LTE aswell as a 5G NR radio for performing communication according to 5G NR.In such a case, the base station 102 may be capable of operating as bothan LTE base station and a 5G NR base station. As another possibility,the base station 102 may include a multi-mode radio which is capable ofperforming communications according to any of multiple wirelesscommunication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTEand UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

As described further subsequently herein, the BS 102 may includehardware and software components for implementing or supportingimplementation of features described herein. The processor 404 of thebase station 102 may be configured to implement or supportimplementation of part or all of the methods described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively, theprocessor 404 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit), or a combination thereof. Alternatively(or in addition) the processor 404 of the BS 102, in conjunction withone or more of the other components 430, 432, 434, 440, 450, 460, 470may be configured to implement or support implementation of part or allof the features described herein.

In addition, as described herein, processor(s) 404 may include one ormore processing elements. Thus, processor(s) 404 may include one or moreintegrated circuits (ICs) that are configured to perform the functionsof processor(s) 404. In addition, each integrated circuit may includecircuitry (e.g., first circuitry, second circuitry, etc.) configured toperform the functions of processor(s) 404.

Further, as described herein, radio 430 may include one or moreprocessing elements. Thus, radio 430 may include one or more integratedcircuits (ICs) that are configured to perform the functions of radio430. In addition, each integrated circuit may include circuitry (e.g.,first circuitry, second circuitry, etc.) configured to perform thefunctions of radio 430.

FIG. 5—Block Diagram of Cellular Communication Circuitry

FIG. 5 illustrates an example simplified block diagram of cellularcommunication circuitry, according to some embodiments. It is noted thatthe block diagram of the cellular communication circuitry of FIG. 5 isonly one example of a possible cellular communication circuit; othercircuits, such as circuits including or coupled to sufficient antennasfor different RATs to perform uplink activities using separate antennas,are also possible. According to embodiments, cellular communicationcircuitry 330 may be included in a communication device, such ascommunication device 106 described above. As noted above, communicationdevice 106 may be a user equipment (UE) device, a mobile device ormobile station, a wireless device or wireless station, a desktopcomputer or computing device, a mobile computing device (e.g., a laptop,notebook, or portable computing device), a tablet and/or a combinationof devices, among other devices.

The cellular communication circuitry 330 may couple (e.g.,communicatively; directly or indirectly) to one or more antennas, suchas antennas 335 a-b and 336 as shown (in FIG. 3). In some embodiments,cellular communication circuitry 330 may include dedicated receivechains (including and/or coupled to, e.g., communicatively, directly orindirectly, dedicated processors and/or radios) for multiple RATs (e.g.,a first receive chain for LTE and a second receive chain for 5G NR). Forexample, as shown in FIG. 5, cellular communication circuitry 330 mayinclude a modem 510 and a modem 520. Modem 510 may be configured forcommunications according to a first RAT, e.g., such as LTE or LTE-A, andmodem 520 may be configured for communications according to a secondRAT, e.g., such as 5G NR.

As shown, modem 510 may include one or more processors 512 and a memory516 in communication with processors 512. Modem 510 may be incommunication with a radio frequency (RF) front end 530. RF front end530 may include circuitry for transmitting and receiving radio signals.For example, RF front end 530 may include receive circuitry (RX) 532 andtransmit circuitry (TX) 534. In some embodiments, receive circuitry 532may be in communication with downlink (DL) front end 550, which mayinclude circuitry for receiving radio signals via antenna 335 a.

Similarly, modem 520 may include one or more processors 522 and a memory526 in communication with processors 522. Modem 520 may be incommunication with an RF front end 540. RF front end 540 may includecircuitry for transmitting and receiving radio signals. For example, RFfront end 540 may include receive circuitry 542 and transmit circuitry544. In some embodiments, receive circuitry 542 may be in communicationwith DL front end 560, which may include circuitry for receiving radiosignals via antenna 335 b.

In some embodiments, a switch (e.g., and/or combiner, multiplexer, etc.)570 may couple transmit circuitry 534 to uplink (UL) front end 572. Inaddition, switch 570 may couple transmit circuitry 544 to UL front end572. UL front end 572 may include circuitry for transmitting radiosignals via antenna 336. Thus, when cellular communication circuitry 330receives instructions to transmit according to the first RAT (e.g., assupported via modem 510), switch 570 may be switched to a first statethat allows modem 510 to transmit signals according to the first RAT(e.g., via a transmit chain that includes transmit circuitry 534 and ULfront end 572). Similarly, when cellular communication circuitry 330receives instructions to transmit according to the second RAT (e.g., assupported via modem 520), switch 570 may be switched to a second statethat allows modem 520 to transmit signals according to the second RAT(e.g., via a transmit chain that includes transmit circuitry 544 and ULfront end 572).

In some embodiments, modem 510 and modem 520 may be configured totransmit at the same time, receive at the same time, and/or transmit andreceive at the same time. Thus, when cellular communication circuitry330 receives instructions to transmit according to both the first RAT(e.g., as supported via modem 510) and the second RAT (e.g., assupported via modem 520), combiner 570 may be switched to a third statethat allows modems 510 and 520 to transmit signals according to thefirst and second RATs (e.g., via a transmit circuitry 534 and 544 and ULfront end 572). In other words, the modems may coordinate communicationactivity, and each may perform transmit and/or receive functions at anytime, as desired.

In some embodiments, the cellular communication circuitry 330 may beconfigured to transmit, via the first modem while the switch is in thefirst state, a request to attach to a first network node operatingaccording to the first RAT and transmit, via the first modem while theswitch is in a first state, an indication that the wireless device iscapable of maintaining substantially concurrent connections with thefirst network node and a second network node that operates according tothe second RAT. The wireless device may also be configured transmit, viathe second radio while the switch is in a second state, a request toattach to the second network node. The request may include an indicationthat the wireless device is capable of maintaining substantiallyconcurrent connections with the first and second network nodes. Further,the wireless device may be configured to receive, via the first radio,an indication that dual connectivity with the first and second networknodes has been established.

As described herein, the modem 510 may include hardware and softwarecomponents for implementing features for using multiplexing to performtransmissions according to multiple radio access technologies in thesame frequency carrier, as well as the various other techniquesdescribed herein. The processors 512 may be configured to implement partor all of the features described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). Alternatively (or in addition),processor 512 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit). Alternatively (or in addition) theprocessor 512, in conjunction with one or more of the other components530, 532, 534, 550, 570, 572, 335 and 336 may be configured to implementpart or all of the features described herein.

In some embodiments, processor(s) 512, 522, etc. may be configured toimplement or support implementation of part or all of the methodsdescribed herein, e.g., by executing program instructions stored on amemory medium (e.g., a non-transitory computer-readable memory medium).Alternatively, the processor(s) 512, 522, etc. may be configured as aprogrammable hardware element, such as an FPGA, or as an ASIC, or acombination thereof. In addition, as described herein, processor(s) 512,522, etc. may include one or more processing elements. Thus,processor(s) 512, 522, etc. may include one or more integrated circuits(ICs) that are configured to perform the functions of processor(s) 512,522, etc. In addition, each integrated circuit may include circuitry(e.g., first circuitry, second circuitry, etc.) configured to performthe functions of processor(s) 512, 522, etc.

As described herein, the modem 520 may include hardware and softwarecomponents for implementing features for using multiplexing to performtransmissions according to multiple radio access technologies in thesame frequency carrier, as well as the various other techniquesdescribed herein. The processors 522 may be configured to implement partor all of the features described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). Alternatively (or in addition),processor 522 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit). Alternatively (or in addition) theprocessor 522, in conjunction with one or more of the other components540, 542, 544, 550, 570, 572, 335 and 336 may be configured to implementpart or all of the features described herein.

FIGS. 6-7—5G NR Architecture

In some implementations, fifth generation (5G) wireless communicationwill initially be deployed concurrently with other wirelesscommunication standards (e.g., LTE). For example, whereas FIG. 6illustrates a possible standalone (SA) implementation of a nextgeneration core (NGC) network 606 and 5G NR base station (e.g., gNB604), dual connectivity between LTE and 5G new radio (5G NR or NR), suchas in accordance with the exemplary non-standalone (NSA) architectureillustrated in FIG. 7, has been specified as part of the initialdeployment of NR. Thus, as illustrated in FIG. 7, evolved packet core(EPC) network 600 may continue to communicate with current LTE basestations (e.g., eNB 602). In addition, eNB 602 may be in communicationwith a 5G NR base station (e.g., gNB 604) and may pass data between theEPC network 600 and gNB 604. In some instances, the gNB 604 may alsohave at least a user plane reference point with EPC network 600. Thus,EPC network 600 may be used (or reused) and gNB 604 may serve as extracapacity for UEs, e.g., for providing increased downlink throughput toUEs. In other words, LTE may be used for control plane signaling and NRmay be used for user plane signaling. Thus, LTE may be used to establishconnections to the network and NR may be used for data services. As willbe appreciated, numerous other non-standalone architecture variants arepossible.

Secondary Cell (Scell) Link Recovery

Modern wireless communication systems, e.g., cellular systems such as 5GNR, may allow for a UE to be connected to multiple cells simultaneously.For example, a UE may connect to a primary cell (PCell) and one or moresecondary cell (SCells). The PCell may handle control communicationsbetween the network and the UE for the SCell(s). The PCell and SCell(s)may operate according to the same or different RATs. For example, thePCell may operate according to LTE and the SCell(s) may operateaccording to NR, or vice versa, among other possible combinations. ThePCell and SCell(s) may be provided by the same or different BS 102.

Under some circumstances, a UE may lose (e.g., disconnect) a link withone or more cells. For example, a UE may declare link failure inresponse to one or more measurements of radio conditions for the linkfalling below one or more corresponding thresholds. The link failure maybe a beam failure, e.g., the UE and BS may need to select newdirectional beams for uplink (UL) and/or downlink (DL) communications.For example, based on a change in orientation of the UE relative to theBS, the UE may need to use a different beam for transmitting and/orreceiving. It will be appreciated that either or both of the UE and/orBS may need to update beam selection in response to a link failure.Similarly, it may be the case that a link failure may lead to thehandover of the UE to one or more different cells.

In NR, it has been agreed that for SCell Link Recovery (LR), e.g., aftera UE declares link failure of a link with an SCell, the UE would send aLink Recovery reQuest (LRQ) in two steps using a PCell, e.g., asillustrated in FIG. 8. In a first step, the UE may send a SchedulingRequest (SR)-like message on a physical uplink control channel (PUCCH)for Link Recovery (LR) to tell the BS (e.g., gNB) of the beam (e.g.,link) failure. The PUCCH-LR may be transmitted using scheduled time andfrequency resources designated for this purpose. In some embodiments,the UE may determine opportunities to transmit an indication of linkfailure prior to such a PUCCH-LR opportunity. In some embodiments, a UEmay use one or more approaches for resolving a conflict (e.g.,collision) between a LR message and one or more other scheduledmessages.

In a second step, the UE may report the failed serving cell index aswell as a new beam index. In some embodiments, the UE may wish toperform one or more UL and/or DL communications prior to receiving anindication from the BS of which UL and/or DL beam should be used. The UEmay use the beam indicated in the report of the second step prior toreceiving such an indication from the BS.

FIG. 9 is a flow diagram which illustrates exemplary aspects of LRmessaging. The techniques of FIG. 9 may allow for a UE to transmit LRmessages to the network efficiently and to select beams forcommunications prior to receiving a beam indication from the network.Aspects of the method of FIG. 9 may be implemented by a UE 106 incommunication with a BS 102, as illustrated in and described withrespect to the Figures, or more generally in conjunction with any of thecomputer circuitry, systems, devices, elements, or components shown inthe Figures, among other devices, as desired. For example, a processor(or processors) of the UE (e.g., processor(s) 302, processor(s)associated with communication circuitry 329 or 330 such as processor(s)512 and/or 522, etc.), base station (e.g., processor(s) 404, or aprocessor associated with radio 430 and/or communication chain 432,among various possibilities), or network element (e.g., any component ofNGC 606, EPC 600, etc.) may cause the UE or base station(s) to performsome or all of the illustrated method elements. For example, a basebandprocessor or application processor of the UE may cause the UE to performsome or all of the illustrated method elements. Note that while at leastsome elements of the method are described in a manner relating to theuse of communication techniques and/or features associated with 3GPPspecification documents, such description is not intended to be limitingto the disclosure, and aspects of the method may be used in any suitablewireless communication system, as desired. In various embodiments, someof the elements of the methods shown may be performed concurrently, in adifferent order than shown, may be substituted for by other methodelements, or may be omitted. Additional method elements may also beperformed as desired. As shown, the method may operate as follows.

A UE 106 may establish a connection with a BS 102 (902), according tosome embodiments. The connection may be or include a cellularconnection, e.g., operating according to one or more wireless standards.The connection may include links with a PCell and one or more SCell(s).The PCell and one or more SCell(s) may be provided by any number of BSs(e.g., one or more BS 102s). The UE and BS(s) may exchange data and/orcontrol information, e.g., in the uplink (UL) and/or downlink (DL)directions. The PCell and SCell(s) may operate according to the same ordifferent wireless standards. For example, one or more of the cells mayoperate according to LTE and/or NR, among various possibilities. Forexample, the PCell may use LTE and an SCell may use NR, or vice versa,or both the PCell and SCell may use NR, among various possibilities.

The UE and/or BS may take various measurements of the various links(e.g., of the PCell and/or SCell(s)). The measurements may include anyradio link measurements such as signal-noise ratio (SNR), signal tointerference and noise ratio (SINR), reference signal received power(RSRP), reference signal received quality (RSRQ), received signalstrength indicator (RSSI), channel quality indicator (CQI), channelstate information (CSI), block error rate (BLER), bit error rate (BER),channel impulse response (CIR), channel error response (CER), etc. TheUE and/or BS may retain a history of measurement values. The UE/BS maycompare the measurement values, or metrics calculated based on themeasured values, to one or more thresholds. The UE/BS may use variousparameters, e.g., for hysteresis, in such comparisons. The measurements,thresholds, and/or parameters may be configured by the BS (e.g., by thenetwork) and/or by the UE. The UE and/or BS may report measurementvalues (e.g., directly and/or as channel quality indicator (CQI),channel state information (CSI), etc.), comparison results, etc. to eachother and/or to the network at any time.

The UE 106 may determine link failure, e.g., of a link with an SCell(904), according to some embodiments. The link failure may be based onone or more measurements falling below corresponding thresholds, e.g.,indicating that the link (e.g., the current beam of the link) has becomeunusable. For example, the link failure of the SCell may be a beamfailure of the SCell. The UE 106 may or may not determine failure ofother links (e.g., other SCells, PCell, etc.). For example, the link tothe PCell may remain useable.

The UE 106 may determine conditions (906), according to someembodiments.

As noted above, it may be beneficial for the UE to transmit anindication of the SCell link failure prior to (e.g., or more generally,outside of) a scheduled opportunity for transmitting a link recoverymessage (e.g., PUCCH-LR). This may allow the UE to skip the PUCCH-LR andto save overhead and reduce latency. For example, if the BS receives amedia access control (MAC) control element (CE) for LR, the BS mayidentify a failed serving cell index (e.g., provided by the UE in theMAC CE and/or identifying the SCell with the link failure), so that itcan identify the beam failure event. For example, as shown in FIG. 10, aUE may declare link failure at a first time, transmit a MAC CE for LR ata second time (e.g., a physical uplink shared channel (PUSCH)opportunity, among various possibilities), and at a third time skip aPUCCH-LR opportunity.

The UE may determine conditions under which it may perform an earlytransmission of a link failure indication, e.g., as shown in FIG. 11,according to some embodiments. For example, in response to detecting oneor more of the following conditions, a UE may skip a PUCCH-LRtransmission.

Condition 1: the UE may receive a UL grant after it declares linkfailure and before the next opportunity of PUCCH-LR. Thus, the UE maydetermine to transmit an indication of link failure on the resources(e.g., PUCCH and/or PUSCH resources) allocated by the UL grant. Theresources allocated by the UL grant may be before or concurrent with thenext opportunity of PUCCH-LR. In some embodiments, the resourcesconfigured by the UL grant may be after the next opportunity ofPUCCH-LR.

Condition 2: the UE may be configured with a configured-grant basedtransmission, e.g., for PUSCH and/or PUCCH resources. For example, theconfigured-grant may allocate resources for periodic and/or ongoingtransmissions such as channel state information (CSI). A portion of theresources allocated by the configured grant may be before or concurrentwith the next opportunity of PUCCH-LR. In some embodiments, the portionof the resources allocated by the configured grant may be after the nextopportunity of PUCCH-LR.

Condition 3: the UE may be configured with a 2-step random accesschannel (RACH) process. For example, the UE may determine that anopportunity to perform 2-step random access (e.g., RACH) may beavailable. The 2-step RACH opportunity may be before or concurrent withthe next opportunity of PUCCH-LR. In some embodiments, the 2-step RACHopportunity may be after the next opportunity of PUCCH-LR. Thus, therandom access request may be used to indicate the link failure of theSCell.

In some embodiments, an additional condition for conditions 2 and/or 3could be that the resources allocated by the configured grant ordesignated for the 2-step RACH opportunity occur prior to a nextopportunity specifically configured for link recovery messages (e.g., aPUCCH-LR opportunity). For example, an additional condition may be thatthere is one PUSCH opportunity for the configured grant or UL grantafter UE declares beam failure and before the next opportunity forPUCCH-LR. In other words, early transmission and skipping of thePUCCH-LR opportunity may only be implemented if the PUSCH opportunity or2-step RACH opportunity is not later than the next opportunity forPUCCH-LR.

In some embodiments, even if one or more of conditions 1-3 are true, theUE may select not to perform early transmission, and may instead waitfor the PUCCH-LR opportunity. Among other possibilities, the UE mayselect to wait for the PUCCH-LR opportunity if a periodicity of aconfigured grant (e.g., in context of condition 2) is sufficiently long(e.g., if skipping the intended transmission of the configured grant mayresult in a long delay and frustration of that purpose).

In various embodiments, an opportunity for transmitting a link failureindication (e.g., based on any of conditions 1-3) may be on any ofvarious cells. In some embodiments, the conditions 1-3 may be furtherlimited based on the type and/or identity of the cell on which theopportunity is found. In some embodiments, the conditions 1-3 may belimited to the case that the serving cell (e.g., the cell on which theopportunity to transmit the link failure indication exists) is the sameas the cell on which the PUCCH-LR opportunity exists. In someembodiments, the conditions 1-3 may be limited to the case that theserving cell is the same as the cell on which the PUCCH-LR opportunityexists or any other serving cell (e.g., the PCell or any SCell). In someembodiments, the conditions 1-3 may be limited to the case that theserving cell is the same as the cell on which the PUCCH-LR opportunityexists or another serving cell excluding the failed serving cell (e.g.,the PCell or any SCell other than the SCell on which the link failureoccurred).

In some embodiments, the UE may detect that it is not configured for anyPUCCH-LR resource (e.g., a fourth condition). Accordingly, the UE mayfallback to use contention based PRACH to request resources fortransmitting a MAC CE for LR, e.g., as shown in FIG. 12 according tosome embodiments. In response to detecting the link failure of an SCelland further determining that the UE is not configured with a PUCCH-LRopportunity (e.g., at all, or within a threshold amount of time), the UEmay transmit a contention based (CB) PRACH to the network. The CB PRACHmay be transmitted on the PCell, on the SCell where the link failureoccurred, or on another SCell, among various possibilities. The networkmay transmit a random access response (RAR). The RAR may include a cellradio network temporary identifier (C-RNTI). In response to the RAR, theUE may transmit a MAC CE for LR, e.g., using the C-RNTI. In response tothe MAC CE, the network may transmit a contention resolution to the UE.The contention resolution may indicate a new beam (or beams) for ULand/or DL communications on the failed SCell. The contention resolutionmay also include one or more UL and/or DL grants.

In some embodiments, the UE may detect one or more collisions orconflicts with PUCCH-LR and one or more other UL transmissions (e.g., orconfigured transmission opportunities). As illustrated in FIG. 13, suchcollisions may include UL transmissions using any of varioustransmission (Tx) beams on any of various cells, according to someembodiments. Accordingly, the UE may determine conditions to inform adecision of how to transmit PUCCH-LR when it is collided with othersignals in the same cell or different cells. For example, a UE may beable to use only one Tx beam to transmit a UL signal in a transmissionoccasion, therefore may need to determine how to handle the case whenPUCCH-LR and other signals with different beams are multiplexed (e.g.,in frequency division multiplexing (FDM)). For example, in theillustrated case, the UE may need to select one of the PUCCH-LR using Txbeam 1 on the PCell, PUSCH using Tx beam 2 on a first SCell, or SRSusing Tx beam 3 on a second SCell. In other words, when PUCCH-LRcollides with one or more other UL signal, the UE may use a priorityrule to determine which signal to drop. For example, based on thepriority rule, the UE may determine to transmit either the PUCCH-LR orthe other UL signal, but not both (at least not at the time of thecollision). Accordingly, in order to implement such a priority rule, theUE may determine what (e.g., if any) other UL transmission collides withthe PUCCH-LR opportunity and on what cell or cells the othertransmission is configured.

In an example in which the PUCCH-LR collides with another UL signal on adifferent serving cell an example priority rule may be expressed as:PRACH is higher priority than PUCCH-LR, PUCCH-LR may be higher prioritythan other PUCCH communications, which may be higher priority thanreference signal (e.g., sounding reference signal (SRS)). In otherwords: PRACH>PUCCH-LR>PUCCH for any other purposes (e.g., such asscheduling request (SR), hybrid acknowledgement request (HARQ)acknowledgment (ACK), CSI, etc.) >SRS. It will be appreciated that thispriority rule is exemplary only, and that other priority rules may beused as desired.

In an example in which the PUCCH-LR collides with another uplink signalin the same serving cell, the following priority rules may be used,among various possibilities. In a first case that the PUCCH-LR collideswith PRACH, the UE may transmit PRACH. In some embodiments, in the firstcase, the UE may determine to transmit PUCCH-LR, e.g., according to analternative priority rule. In a second case that the PUCCH-LR collideswith PUSCH, the UE may transmit MAC CE for LR using the PUSCH resources,e.g., and may skip transmission of PUCCH-LR. In a third case that thePUCCH-LR collides with PUCCH for another purpose, the UE may drop theother PUCCH in order to transmit the PUCCH-LR. It will be appreciatedthat other priority rules may be used as desired. In some embodiments,if other resources for indicating link failure are available (e.g.,according to conditions 1-3, discussed above), then the PUCCH-LR may beconsidered low priority, and any of the above example priority rules maybe modified to reduce the priority of PUCCH-LR, e.g., relative tocolliding transmission types.

The UE 106 may transmit an indication of link failure the BS 102 (908),according to some embodiments. The indication of link failure may betransmitted on time and frequency resources selected based on theconditions and priority rules described above (e.g., with respect to906). For example, if any of conditions 1-3 apply, the UE may transmitthe indication of link failure on resources available prior to PUCCH-LRresources and may skip transmission of the PUCCH-LR, among variouspossibilities. As another example, (e.g., if no previous transmitopportunities are identified), the UE may determine to transmit PUCCH-LRinstead of transmitting a lower priority UL transmission that collideswith the PUCCH-LR transmission opportunity.

In some embodiments, the indication of link failure may include arecommended UL and/or DL beam, e.g., for further communication with theSCell on which link failure occurred. Such a recommended UL and/or DLbeam may be determined based on measurements of one or more beams, basedon motion of the UE, and/or other factors.

The network may transmit and the UE may receive a response to theindication of link failure (910), according to some embodiments. Theresponse may be or include an acknowledgement (ACK). The response mayinclude UL and/or DL resource assignments, e.g., for the SCell on whichthe link failure occurred and/or other cells. The response may betransmitted on the PCell, among various possibilities. In someembodiments, the response may not include an indication of a selected ULand/or DL beam for use with the failed serving cell (e.g., the SCell onwhich link failure occurred). In other words, the response may notrespond to any indication of a suggested beam that the UE included in anindication of link failure (e.g., in 908).

The UE 106 may select a beam or beams for UL and/or DL communicationwith the BS 102, e.g., for communication on the SCell on which linkfailure occurred (912), according to some embodiments. In someembodiments, such a selection may occur without (e.g., prior to)receiving an indication from the network of what beam to use subsequentto the link failure, e.g., as shown in FIG. 14. Selecting a beam withoutwaiting for an indication of a beam selected by the network may allowfor the UE to proceed with communications with less latency (e.g.,without waiting to receive an indication of the network's selectedbeam). As shown, the UE may transmit an indication of the link failure(e.g., a MAC CE for LR, among various possibilities) (e.g., as in 908)and may receive a response from the network (e.g., as in 910). Based onthe response (e.g., and/or based on a UL/DL grant, configured grant,etc.), the UE may determine that a UL and/or DL transmission isscheduled, on the SCell on which the link failure occurred, prior toreceiving any UL and/or DL beam indication from the network for theSCell on which the link failure occurred. Accordingly, the UE may selecta UL and/or DL beam prior to receiving such an indication. In otherwords, the UE may make a quasi co-location (QCL) assumption for a DLsignal and/or a spatial relation information assumption for an ULchannel after transmitting the link failure indication and receiving aresponse. For example, when LR is finished successfully, the previousbeam (e.g., on which the link failure occurred) may not be qualified forcommunication (e.g., due to the beam/link failure). Accordingly, the UEmay assume that a beam recommended in the UE's indication of linkfailure (e.g., in 908) may be used if at least a threshold amount oftime has passed since a response (e.g., in 910) to the link failureindication. The threshold amount of time may be expressed as a number ofslots, K. For example, K or more slots after receiving the response to aMAC CE for LR and before beam indication for corresponding channel(e.g., beam), the UE use a beam (e.g., or respective UL and DL beams, ifidentified separately) identified in the indication of link failure totransmit any UL channel and/or receive any DL channel on the SCell onwhich link failure occurred. The UL channel/transmission(s) couldinclude PUCCH, and/or SRS, and/or PUSCH, among various possibilities.The DL channel/transmissions could include PDCCH, and/or PDSCH, amongvarious possibilities. In some embodiments, the UE may apply thisassumption that the indicated beam(s) will be used only for UL and/or DLchannel(s) in the failed serving cell (e.g., only on the SCell on whichthe link failure occurred). In other embodiments, the UE may use thisassumption for UL and/or DL channel(s) in all serving cells in the sameband as the failed serving cell (e.g., potentially including the PCelland/or one or more additional SCells). Thus, the UE may use thesuggested (e.g., assumed) UL and/or DL beam to proceed with furthercommunication to/from the failed serving cell (e.g., and/or other cells)without delay.

In some embodiments, K may be based on a UE capability, e.g., a minimumamount of time in which the UE can change from one beam to another. Insome embodiments, K may be configured by the network, e.g., using radioresource control (RRC) signaling. In some embodiments, K may bepredefined, e.g., by a standards document, e.g. K=4, among variouspossibilities.

In some embodiments, the UE may further receive an indication from thenetwork of a UL and/or DL beam, selected by the network, to use with theSCell on which link failure occurred (e.g., and potentially all servingcells in the same band as the failed serving cell). The UL and/or DLbeam, selected by the network, may be the same or different than thebeam(s) suggested by the UE (e.g., in 908). Accordingly, if the beam(s)are different than the beam(s) suggested (e.g., in 908) and used (e.g.,in 912), the UE may switch to the beam(s) selected by the network (e.g.,for further UL and/or DL communications with the failed serving SCelland/or other serving cells operating in the same band as the failedserving cell).

Additional Information and Examples

In some embodiments, the techniques of FIG. 9 may be used to handlefailures of multiple SCells at the same or similar times. For example,an indication of link failure may identify multiple SCells, e.g., bytheir respective cell indexes. Similarly, transmissions to/from multipleSCells may use beams indicated in a beam indication transmitted to thenetwork prior to receiving a corresponding beam indication from thenetwork.

Embodiments of the present disclosure may be realized in any of variousforms. For example, some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE) may be configured to includea processor (or a set of processors) and a memory medium, where thememory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement anyof the various method embodiments described herein (or, any combinationof the method embodiments described herein, or, any subset of any of themethod embodiments described herein, or, any combination of suchsubsets). The device may be realized in any of various forms.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A user equipment device (UE), comprising: aradio; and a processor operably coupled to the radio and configured tocause the UE to: establish a connection with a cellular network, whereinthe connection includes: a link to a primary cell (PCell); and a link toa secondary cell (SCell); and determine a failure of the link to theSCell; determine at least one condition for early transmission of anindication of the link to the SCell; and transmit, to the cellularnetwork, the indication, wherein the indication is transmitted outsideof an opportunity for transmission of a link recovery message inresponse to the determination of the at least one condition.
 2. The UEof claim 1, wherein the at least one condition includes a detection ofan uplink grant, wherein the indication of the failure of the link tothe SCell is transmitted on resources allocated by the uplink grant. 3.The UE of claim 1, wherein the at least one condition includes that theUE is allocated resources by a configured grant, wherein the indicationis transmitted on the resources allocated by the configured grant. 4.The UE of claim 3, wherein the at least one condition further includesthat the resources allocated by the configured grant are before a nextopportunity for transmission of a link recovery message.
 5. The UE ofclaim 1, wherein the at least one condition includes that the UE isconfigured for 2-step random access, wherein transmitting the indicationincludes transmitting a random access request.
 6. The UE of claim 5,wherein the at least one condition further includes that resources for2-step random access are before a next opportunity for transmission of alink recovery message.
 7. The UE of claim 1, wherein a first conditionof the at least one condition includes that the UE is allocatedresources by a configured grant, wherein a second condition of the atleast one condition includes that the periodicity of the configuredgrant is longer than a threshold, wherein the indication is nottransmitted on the resources allocated by the configured grant inresponse to the second condition.
 8. An apparatus for operating a userequipment device (UE), the apparatus comprising: a processor configuredto cause the UE to: establish a connection with a secondary cell (SCell)of a cellular network; determine that the connection with the SCell hasfailed using a first beam; transmit, to the cellular network, anindication of the link failure, wherein the indication of the linkfailure includes an indication of a suggested beam for furthercommunications with the SCell; receive, from the cellular network, aresponse to the indication of the link failure; select a second beam fora first further communication with the SCell, wherein the second beam isthe suggested beam; and perform the first further communication with theSCell using the second beam prior to receiving an indication from thenetwork of a selected beam.
 9. The apparatus of claim 8, wherein theprocessor is further configured to cause the UE to: receive, from thecellular network, the indication of the selected beam, wherein theselected beam is a third beam different from the second beam; and usethe third beam for a second further communication with the SCell,wherein the second further communication with the SCell is subsequent tothe first further communication with the SCell.
 10. The apparatus ofclaim 8, wherein the second beam is used only for the SCell.
 11. Theapparatus of claim 8, wherein the second beam is used for all servingcells operating in a same band as the SCell.
 12. The apparatus of claim8, wherein the first further communication occurs at least K slots afterreceiving the response to the indication of the link failure.
 13. Theapparatus of claim 12, wherein K is based on an indication received fromthe network via radio resource control signaling.
 14. The apparatus ofclaim 12, wherein K is based on a capability of the UE.
 15. An apparatusfor operating a user equipment device (UE), the apparatus comprising: aprocessor configured to cause the UE to: connect to a secondary cell(SCell) of a cellular network using a first beam; based on one or moremeasurements, declare link failure associated with the SCell and thefirst beam; determine that a physical uplink control channel (PUCCH)link recovery (PUCCH-LR) opportunity on a primary cell (PCell) of thecellular network collides with a first other uplink transmissionopportunity; select one of the PUCCH-LR opportunity or the first otheruplink transmission opportunity, based on a priority rule; transmit, tothe PCell and according to the selection, an indication of the linkfailure associated with the SCell and the first beam; and perform afurther communication with the SCell using a second beam different fromthe first beam.
 16. The apparatus of claim 15, wherein the first otheruplink transmission opportunity is scheduled for a serving celldifferent than the PCell.
 17. The apparatus of claim 16, wherein thefirst other uplink transmission opportunity is a PUCCH opportunity for apurpose other than link recovery.
 18. The apparatus of claim 15, whereinthe first other uplink transmission opportunity is scheduled for thePCell.
 19. The apparatus of claim 18, wherein the first other uplinktransmission opportunity is a physical uplink shared channel (PUSCH)opportunity, wherein transmitting the indication of the link failure isperformed using resources of the PUSCH opportunity.
 20. The apparatus ofclaim 19, wherein the PUCCH-LR opportunity is skipped.